Revolvers develop some end play in the cylinder after prolonged usage. This condition, known as end shake cylinder, results from the constant impact imparted to the cylinder by the firing pin during firing. End shake cylinder is an undesirable condition which can cause misfires if the play becomes excessive.
Typically, the cylinder of a revolver rotates on a forked support member known as a crane or yoke. The crane has two legs, called the barrel and the stud, which are connected by a body portion. The stud fits into an aperture in the weapon frame and the crane barrel supports the cylinder. It is the length of the crane barrel which determines the amount of end play in the cylinder. With wear the crane barrel length becomes shorter, increasing the end play. The length of the barrel must be very precise to assure free rotation of the cylinder without permitting excessive end play. Therefore, the crane is not a part which is interchangeable between weapons. Each crane must be precisely fit in length to the particular weapon frame and cylinder with which it will be used. For this reason, it is not possible to simply obtain and install a new crane as end shake develops.
In the past it has been necessary to return the weapon to the manufacturer for repair, or to have the repair performed by an experienced pistolsmith. This is a difficult repair procedure and can easily be worsened in inexperienced hands. The present repair procedure requires removal of the crane from the weapon and insertion of a steel rod or liner into the bore of the crane barrel. The crane is then placed against a steel block and peened about its circumference near the end of the crane barrel. The peening causes deformation of the metal, resulting in expansion of the crane barrel length. The barrel of the crane can then be carefully filed back to obtain the correct fit once again. Frequent reassembly is required to check for proper fit. If too much metal is removed, or if the crane barrel end is not filed perfectly square, the repair is ruined, necessitating factory repairs.
An alternate method of repair involves inserting small hardened washers into the cylinder bore to remove the end shake. Many times the washers become imbedded in the cylinder, making removal impossible and causing binding in the rotation of the cylinder. Therefore, this method of repair is often unsatisfactory.